1. Field of the Invention
The present invention relates to a secondary battery having an insulating case. The insulating case has grooves through which electrode tabs protruding from an electrode assembly can be drawn. The insulating case has spare grooves, and therefore, can be used in a variety of designs of the secondary batteries.
2. Description of the Related Art
Rechargeable secondary batteries are economical over disposable dry cells. In recent years, as low-volume and high-capacity secondary batteries are developed, they are widely used as power supplies for portable electronic/electrical devices, such as cellular phones, camcorders, notebook computers and the like.
The secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among them, the lithium secondary batteries are most widely used because of their small size, high capacity, high operating voltage, and high energy density per weight.
The lithium secondary batteries may be classified into can-type lithium secondary batteries and pouch-type lithium secondary batteries depending on shapes of a casing, which accommodates an electrode assembly having a negative electrode plate, a positive electrode plate and a separator. The can-type lithium secondary batteries may be further classified into cylinder-type lithium secondary batteries and prismatic-type lithium secondary batteries.
When the lithium secondary battery is of the can type, the casing is generally formed of a metal such as aluminum and has a cylindrical shape, a prismatic shape, or a pillar shape with rounded edges.
The can has an upper opening through which an electrode assembly is inserted and electrolyte is injected into the can. The can is then covered by a cap assembly having a size and shape corresponding to the opening of the can, resulting in a sealed bare cell.
When the lithium secondary battery is of the pouch-type, a pouch casing has a space for accommodating an electrode assembly, which is accommodated on a lower surface of the casing.
The lower surface is covered with an upper surface of the pouch casing, and sealing portions are formed at edges of the upper and lower surfaces of the pouch casing and bonded to be sealed, resulting in a bare cell.
The bare cell configured above is electrically connected with a protecting circuit board, which includes a protecting device for preventing accident caused by abnormal operation, such as overcharge, over-discharge, over-current, and the like.
In general, the electrical connection between the bare cell and the protecting circuit board is made via a lead. Such a secondary battery may be called a core pack.
The core pack is received in an outer case or a gap of the core pack is filled with a hot-melt resin. The core pack is then subjected to a tubing process with a thin casing and a labeling process, resulting in a battery pack.
When the lithium secondary battery is of a prismatic type, an insulating case is positioned on a top of the electrode assembly. The insulating case electrically insulates the electrode assembly from the cap assembly, and fixes the positions of positive and negative electrode tabs protruded from the electrode assembly.
At this time, only one groove for fixing the position of the positive electrode tab is formed at one side of the insulating case. For this reason, when the position of the positive electrode tab is changed due to a different length of an electrode plate, the shape of the insulating case may also be changed. Therefore, efficiency of processes may be degraded as the shape of the insulating case is changed.